A biopsy entails the surgical removal of tissue or cells from the body of a patient for pathological examination of the collected sample. The purpose for taking a biopsy sample is often to look for cellular shape changes represented in the collected sample. The identification of particular cellular shape changes in a collected specimen can be instrumental in the identification of cancer in a patient.
Biopsy tissue samples are required for the diagnosis and treatment of a wide range of diseases and disorders that often require a physician to access the tortuous and relatively small cross-sectional areas of a patient's internal anatomical body lumens. A patient's pancreaticobiliary system (including the anatomical regions of the gall bladder, pancreas, and the biliary tree), for example, is accessed for retrieval of biopsy samples for the treatment of disorders of certain portions of the digestive system.
The biliary system delivers bile produced by the liver to the duodenum where the bile assists other gastric fluids in digesting food. The biliary system includes the liver, as well as a plurality of bodily channels and organs that are disposed between the liver and the duodenum. Within the liver lobules, there are many fine “bile canals” that receive secretions from the hepatic cells. The canals of neighboring lobules unite to form larger ducts, and these converge to become the “hepatic ducts.” They merge, in turn, to form the “common hepatic duct.” The “common bile duct” is formed by the union of the common hepatic and the cystic ducts. It leads to the duodenum, where its exit is guarded by a sphincter muscle. This sphincter normally remains contracted until the bile is needed, so that bile collects in the common bile duct and backs up to the cystic duct. When this happens, the bile flows into the gallbladder and is stored there. Sometimes, however, lesions may grow in portions of the biliary system, for example, one of the biliary ducts, that impede bile from properly flowing through the system. In some cases, the lesions may completely prevent the bile flow. This is undesirable as it interrupts the regular digestive process and may even cause damage to the channels and organs of the biliary system.
In order to properly treat the lesions, it is sometimes necessary to acquire a biopsy tissue sample from the lesion, analyze the sample, and then determine a proper treatment based on the analysis, such as, for example, chemotherapy for the treatment of a cancerous mass.
Endoscopes are often used to access and visualize a patient's anatomical lumen, such as those in the pancreaticobiliary system, during a medical procedure. Once the endoscope is positioned in the desired body portion, a biopsy instrument can be advanced through the working channel of the endoscope to the desired body portion. The endoscope and biopsy instrument may then be manipulated as desired for visualization and specimen sampling respectively.
Smaller diameter endoscopes are presently available in the endoscopy market that help reduce unnecessary trauma to the tissues of a patient and provide more versatile endoscopes capable of accessing more diverse categories of patient body lumens. With these smaller diameter endoscopes comes necessarily smaller working channels, which limit the size of any auxiliary instrument used. This, in turn, limits the size of any biopsy specimen collected.
Biopsies are often performed with a biopsy instrument having forceps with two jaws activated by an internal manipulating wire or wires. The instrument is passed through an endoscope to a desired location and then the jaws are closed to grab and sever the biopsy sample. The instrument with the detached specimen is then withdrawn from the endoscope so that the sample is removed. Frequently, due to a small moment arm of the instrument, the cutting, biting, shearing, or tearing force of the jaws is not sufficient or the jaws are not sharp enough (often due to machining tolerances imposed on small diameter elements) to cleanly shear the tissue which is then torn off by a pulling movement. This is particularly problematic in smaller diameter endoscopes with smaller diameter working channels. Accordingly, additional structural jaw features are desired that allow for improved tissue retrieval and improved sample retention, particularly where the desired treatment lumen is of a relatively small cross-section and/or the working channel of the endoscope is relatively small.
Thus, it is desirable to have a miniature biopsy forceps assembly that can access small working channels of smaller endoscopic devices, more precisely access the tortuous and relatively small cross-sectional areas of certain anatomical body lumens, and both sever and retain tissue samples adequate for pathology study.